Cycads: the Lowveld National Botanic Garden's approach to their management

J.P. Kluge

Lowveld National Botanic Garden, National Botanical Institute,
P.O. Box 1024, Nelspruit 3206, South Africa


Abstract

This paper describes the strategy that the Lowveld National Botanic Garden applies in its effort to play a significant role in trying to save endangered plants on a long-term basis.

The practical policy of our Garden with regard to the endangered species of our area is discussed.

The Lowveld National Botanic Garden is concentrating on Encephalartos species. We have more than 1000 species in the Garden. The philosophy behind the planting of Encephalartos seed orchards and the integrated policy with Nature Conservation authorities will be discussed. Remarks on our pollinating techniques will also be discussed, as well as our germinating and growing-on techniques. The amount of seed to be produced will be mentioned, as well as the ways of distributing seed or seedlings produced in the Garden.


The Lowveld National Botanical Garden is one of eight gardens run by the National Botanical Institute (NBI). It is situated in the Eastern Lowveld of South Africa which has a subtropical climate and receives an average of 750 mm of rain per annum, mostly in summer.

The cycad project as run by the Lowveld Garden fullfils two of the main objectives of the NBI, namely:

South Africa is home to 34 cycad species, of which 33 belong to the genus Encephalartos and one to Stangeria. Of the 16 species (including one undescribed species) occurring in the Transvaal, only three are not endangered and all are found in the vicinity of the Lowveld Garden, making it an obvious choice for conservation efforts.

Some ten years ago the Garden began in earnest with the collecting of endangered Encephalartos species. However, it soon became apparent that the housing of this collection in the display area of the Garden was impractical, for several reasons. Experimental work could not be easily carried out in an area of the Garden accessible to the public; more plants were needed if a genetically sound population was to be maintained and if sufficient seed was to be produced to meet both research and commercial requirements.

A decision was therefore taken to adopt a new approach to the management of the Encephalartos collection, whereby about 100 individuals of each species were to be planted in seed orchards in an area of the Garden not open to the public. Seeds would be collected from every known cycad locality and established in orchards, each of which would be representative of a particular locality. For instance, the three known populations of E. lebomboensis would be treated as three different taxa and the seed established in three separate orchards. This procedure would minimize the mixing of gene pools and therefore eliminate potential problems caused by outbreeding depression.

The first seed collections of E. lebomboensis were made from Transvaal reserves by the Nature Conservation authorities in 1987 and the plants established in orchards at Hartebeeshoek. In 1990 this entire collection, which later came to include mature specimens confiscated from unlicensed growers, was donated to the Lowveld Garden. The combined holdings constitute one of the most important cycad collections in South Africa, particularly since the Nature Conservation stock included species extinct in the wild.

The following seed orchards have been established:

Total mature plants
in seed orchard
Seedlings in nursery Seed in holding
E. aemulans 1000
E. arenarius 17
E. cerrinus 51
E. cupidus 111
E. dolomiticus 1850
E. dyerianus 200
E. eugenemaraisii 1325
E. heenanii107
E. humilus181
E. inopinus5030
E. laevifolius50
E. lebomboensis (Jozini)100
E. lebomboensis (Mananga) 60
E. lebomboensis (Piet Retief) 35
E. middelburgensis171000
E. natalensis (Hlobane)100
E. natalensis (Msinga)8
E. ngoyanus (Jozini)281000
E. ngoyanus (Ngoye)20
E. paucidentatus91
E. umbeluziensis50
E. venetus16
E. villosus (Stegi)10
Stangeria eriopus88


Of the abovementioned plants in seed orchards, the following have already produced seeds: E. cupidus, E. dolomiticus, E. venetus and Stangeria eriopus.

Plants in seed orchards are all handfertilised using the dry pollination method whereby male cones are removed from the parent plant when ripe. Pollen is collected, stored and blown by means of a hand pipette on to female cones as they open.

The Lowveld Garden works closely with the Transvaal Nature Conservation authorities who monitor the status of cycad populations in the wild, determine which require augmentation with nurserygrown plants and eventually establish these plants in appropriate habitats. Special consideration is given to critically rare species such as E. dolomiticus and E. cerrinus. Other collaborative efforts include the hand-pollinating, by garden staff, of plants in T.P.A. reserves, particularly in cases where few specimens remain or seed is known to have low fertility. The Lowveld Garden harvests 10% of seed thus fertilised.

A small commercial nursery, where surplus plants are available for sale to the public, forms part of the Lowveld Garden cycad management plan. The ready availability of the nursery-grown plants will, it is hoped, reduce the demand for plants illegally taken from the wild. With the seed orchards coming into production, a range of the more common cycad species and two of the rare species, namely E. dyerianus and E. aemulans, are now available as seedlings. When full production is reached (in the year 2000), the seed orchards should be capable of producing a minimum of 50 000 seeds per annum.

This multifaceted management plan is expected to make a major contribution to the conservation of a scientifically and horticulturally valuable genus.

Preface  |  Contents List  |  Congress Report  |  Workshop Conclusions  |  List of Authors